We know umpires don't call the same strike zone for every count. What we didn't know before now is that the inconsistency produces more correct calls.

Baseball fans have long known, or at least suspected, that umpires call balls and strikes differently as the count changes. At 0-2, it seems that almost any taken pitch that is not right down the middle will be called a ball, while at 3-0 it feels like pitchers invariably get the benefit of the doubt. One of the earliest discoveries made possible by PITCHf/x data was the validation of this perception: Researchers confirmed that the effective size of the strike zone at 0-2 is only about two-thirds as large as in a 3-0 count.

One common explanation offered for this pattern is that umpires don’t want to decide the outcome of a plate appearance. Preferring to let the players play, this argument goes, umpires will only call “strike three” or “ball four” if there is no ambiguity about the call. As Etan Green observed at Five Thirty Eight: “Umpires call balls and strikes as if they don’t want to be noticed.” The data, however, do not support this theory. The called zone shrinks in all pitchers’ counts, even those with only one strike. Similarly, the impact of ball three on zone size is no greater than that of ball one or two. So umpires do not have any particular aversion to ringing up a batter, nor to granting him a free pass. Something else is going on.

A theory that fits the data better, first offered by John Walsh in 2010, is that umpires are putting their thumb on the scale for either the pitcher or the hitter, depending upon the situation. Suggesting that “major league umpires are a compassionate bunch of guys [who] can’t help pulling for the underdog,” Walsh argued that umpires act unconsciously to help whomever is at a disadvantage at any given count, giving pitchers a more generous zone in hitters’ counts and vice versa.

Five years ago, economists found evidence of umpire discrimination based on race. Two new academic papers investigate further.

Caught Lookingexamines articles from the academic literature relevant to baseball and statistical analysis. This review covers three articles on the topic of racial discrimination by umpires. The goal, as always, is to expose the academic frontier to a wide audience and seek ways to move the discussion forward.

Sports can sometimes provide an interesting laboratory to examine pressing social questions that are hard to analyze in other places. It’s hard to measure whether two accountants have different salaries because they have different productivity levels or because one might face discrimination in the labor market. With sports, and especially baseball, a wealth of data allows us to measure productivity with a precision not available in most industries.

When a totally new system like Major League Baseball’s expanded instant replay—complete with brand-new job descriptions and job openings and technology—is assembled on the eve of the season, you’d imagine its implementation would look more like an evolution than the arrival of a fully formed process.

And by most accounts it has been. Whether it’s the change in the transfer rule that tangentially went along with it, or managers getting used to the silly choreography of how to argue with an umpire while simultaneously looking back at the dugout for a thumbs-up or a thumbs-down, everybody involved in the process seems to be getting better at it.

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Despite replay, ejections aren't down (or aren't down by much) this year.

I remember last summer, the day after Bob Melvin had been ejected in what would turn out to be an extra-innings loss to the Astros, Melvin talking to the media in the dugout. He was abashed to have been ejected from such a game. I wasn’t trying to get run, he stressed. As opposed to all the other ejections we see.

On June 5th, 2013, Mike Aviles came up to bat in the top of the ninth with his Indians trailing the Yankees by two runs. With Joe Girardi watching anxiously and Mariano Rivera warming in the bullpen, CC Sabathia was working hard to go the distance. Sabathia had been roughed up a bit, but he was commanding his fastball well. He had managed to keep the complete game in reach by allowing only one walk and striking out eight hitters through as many innings.

Last January, Ben Lindbergh asked Evan Brunell for his assistance in deciphering the previously almost unintelligible arguments conducted during baseball games by people who don’t even play. The result was this article on the best manager-umpire arguments of 2012. Evan followed up on that piece with a sequel at Deadspin on the best manager-ump arguments of the first half of last season, and now he ties a bow on 2013 with a roundup of the best verbal battles that took place after last All-Star break. With the advent of expanded instant replay, the future of manager-umpire arguments has never been less clear. But the manager-ump arguments of the past have never been clearer.

What do expanded replay's early returns tell us about how well the expanded replay system will work this season?

I give it one year until there’s a fundamental change to Major League Baseball’s new replay system.

I’d give it even less time if we weren’t less than three weeks from baseball season. While MLB certainly isn’t opposed to going seat-of-the-pants on this, the league probably won’t want to make another major change so soon.

Why the expansion of replay review makes it more vital that MLB give umpires a voice.

Picture this. You’re at a ballgame. Yeah, you. At a baseball game. You’re sitting behind the third base dugout when this play happened.

Max Scherzer, who was not pitching that day, was ejected from the game. But you didn’t know that. You bought expensive Yankee Stadium seats with prices well into the triple digits for your family and had no idea who was ejected—whether it was Torii Hunter, someone due up later in the inning, a bench coach, a bat boy, it could have been anybody.